How can I solve this error with Package Manager?

Unity Engine
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1

Hello, so these last 3 days I’ve been trying to resolve the following error, it happens whenever I open the Package Manager, in My Assets, also when trying to download an asset and when trying to import it:

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IsReadOnly is not implemented by this handler UnityEditor.PackageManager.UI.Window:ShowPackageManagerWindow(UnityEditor.MenuCommand)

IsReadOnly is not implemented by this handler UnityEditor.EditorApplication:Internal_CallDelayFunctions()

IsReadOnly is not implemented by this handler UnityEditor.EditorApplication:Internal_FocusChanged (bool)

IsReadOnly is not implemented by this handler UnityEngine.GUIUtility:ProcessEvent(int,intptr,bool&)

IsReadOnly is not implemented by this handler UnityEditor.AsyncHTTPClient:smile:one (UnityEditor.AsyncHTTPClient/State,int)

IsReadOnly is not implemented by this handler UnityEditor.PackageManager.UI.Internal.AssetStoreDownloadManager/DownloadDelegateHandler:OnDownloadProgress (string,string,ulong,ulong,int)

Failed to import package with error: Couldn't decompress package UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

Versions where this error showed: 2021.3.8f1 & 2022.1.14f1

I’ve been looking everywhere and I haven’t found a real fix for this, so I will try to list all the things I’ve tried:

  • Restart Unity

  • Restart Unity Hub

  • Log-out and log-in

  • Reinstalling Unity

  • Installing new Unity Version

  • Resetting packages to defaults

  • Updating all modules

  • Deleted the Asset Store-5.x folder

  • I made sure I had enough space in my disk

  • Renaming Unity Packages (making sure there is no wierd characters or spaces)

  • Renaming Folders (making sure there is no wierd characters or spaces)

  • Went to Project Settings > Player > Other Settings > Scripting Backend and changed it from Mono to IL2CPP

I’m kinda desperated already, but hopefully someone can help me solve this.

2 Likes
2

I am having the same issue now. I have done pretty much all of the same troubleshooting.

A lot of my assets won’t import.

3

Extra unwanted packages in new projects (collab, testing, rider and other junk):

About the fastest way I have found to make a project and avoid all this noise is to create the project, then as soon as you see the files appear, FORCE-STOP (hard-kill) Unity (with the Activity Manager or Task Manager), then go hand-edit the Packages/manifest.json file as outlined in the above post, then reopen Unity.

Sometimes the package system gets borked from all this unnecessary churn and requires the package cache to be cleared:

4

do you resolve the issue?

5

9156155--1273385--upload_2023-7-19_15-50-49.png
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I resolved it.

clean/redirect/reset the cache folder for package manager

1 Like
6

The solution provided by #5 works for me.
And I find another probable reason which may cause this issue: the names of your cache folder and asset folder may include invalid letters or punctuation mark. I used to store my assets under D://cache!/…, where the “!” may be the cause…

7

721×770 29.5 KB

I am trying to extract Stronghold Definitive Edition graphic assets (see above). Keep getting the
‘Failed to import package with error: Couldn’t decompress package’ error. How can I go about this?

8

Found another solution, navigate to the package, press the download button and immediately pause it. After a while unpause it and it downloads without any error !

1 Like